Effects of Heat Treatment on Microstructure of Sputter Deposited TiNiPd Film on Si Wafer

Abstract:

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Amorphous thin Films of Ti51.78 Ni22.24Pd25.98 alloys were deposited onto 2 inch diameter n-type (100)Si wafer by r.f. magnetron sputtering. The crystallization temperature from an amorphous state to crystallization of free-standing thin film was found to be 553.1oC, but that of non-free-standing thin film on Si wafer was found to be higher from X-ray diffraction experiment. The film heated 1 h at 550 oC was partly crystallized but at 650 oC was almost whole crystallized. The film heated 1 h at 750 oC quite crystallized and some precipitation appear. Heated 50 h at 450
oC before crystallization the films would be accelerate B19' but restrain B19 formation in succeeding heat-treatment.

Abstract: Transparent phosphosilicate glass-ceramics were prepared by heating the spontaneously crystallized precursor glasses in which crystals have formed during cooling of the melts. And the effects of compositional variation on the crystalline phases, degree of crystallization and transparency were investigated by using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). It is found that Mg2+ tends to exist in silicate-rich phase rather than phosphate-rich phase, such MgO is more beneficial to the transparency of phosphosilicate glass-ceremics compared to CaO. In addition, the substitution of P2O5 for SiO2 enhances the tendency of phase separation, and hence the precipitation of Na2MgSiO4 crystals for the precursor glasses as well as glass-ceramics with good transparency.

Abstract: Formation behavior of nanovoids during the annealing of amorphous Al2O3 and WO3 was studied by transmission electron microscopy. The density and size of the voids in Al2O3 and WO3 increase with increasing annealing temperature from 973 to 1123 K and from 573 to 673 K, respectively. It is suggested that the formation of nanovoids during annealing is attributed to the large difference in density between as-deposited amorphous and crystalline oxides.

Abstract: Nano- crystallization of Fe55Cr18Mo7B16C4 bulk amorphous alloy has been analyzed by X- ray diffraction, differential scanning calorimetric test, and TEM observations in this research. In practice, crystallization and growth mechanism were evaluated using DSC tests in four different heating rates (10, 20, 30, 40 K/min) and kinetic models. A two -step crystallization process was observed in the alloy in which α – Fe, Fe23B6, and Fe3C phases were crystallized in the structure after annealing process. In addition, activation energy for the first step of crystallization process (i.e. α – Fe phase) was measured to be 276 (kj/mol) and 290 (kj/mol) according to Kissinger and Ozawa models respectively. Avrami exponent calculated from DSC curves was 2 and a three -dimensional diffusion controlled mechanism with decreasing nucleation rate was observed in the alloy. Further, it is known from the TEM observations that crystalline α – Fe phase nucleated in structure of the alloy in an average size of 10 nm and completely mottled morphology.